The present invention relates to an endoscope and, more particularly, to an endoscope having a guide member for guiding a treating unit such as catheter or forceps.
An endoscope has in general an operation section, a slender insertion section extending from the operation section, and a connection section. Recently, an endoscope having a treating unit guide member at the end structure of an insertion section has been proposed to guide the end of a treating unit, such as a catheter or forceps, introduced to the end of the insertion section through a channel for the treating unit. In this endoscope, the guide member is rotatably provided by a supporting shaft in a chamber formed at the end of the insertion section. An operating wire is connected at one end thereof to the guide member through a rotary ring in the guide member. The wire extends to the operation section through the insertion section. The leading direction of the treating unit may be altered by pulling or pushing the wire to rotate the guide member.
The end of the insertion section is very small, the installing space of the guide member is restricted, and the supporting shaft for supporting the guide member must be short. Thus, the engaging length of the guide member with the supporting shaft is very short, and when the guide member is rotating by pulling the wire, a powerful twisting force acts upon the guide member in addition to the rotary force around the supporting shaft. The guide member rubs against the side walls of the chamber for operating as the guide of the guide member. Consequently, the guide member increases its resistance in the rotating mode, and an operator can feel a lull in the operating force of the guide member. Moreover, this resistance decreases the operability of the endoscope. Further, there arise defects, i.e., the wire stretches, the wire is removed from the guide member, or a guide pipe for the wire is bent.